The present invention relates to a tape cartridge, and more particularly to a tape cartridge having an improved housing structure which is capable of preventing inadvertent writing on a magnetic recording tape on which data is stored.
Two-reel tape cartridges in which a magnetic recording tape wound on two tape reels is driven by a flexible elastic belt, are well known. One example of such tape cartridges is disclosed in U.S. Pat. No. 3,692,255 assigned to Minnesota Mining and Manufacturing Company.
U.S. Pat. No. 3,976,262 discloses a tape cartridge having a write enable plug which is disposed on a cartridge housing shiftably between two positions in which writings on a magnetic recording tape are permitted and prevented, respectively. Minnesota Mining and Manufacturing Company has been proposed a mini tape cartridge having an approximate half size of the prior art tape cartridges. The tape cartridge is discussed with reference to FIGS. 4 and 5 of the present application. The tape cartridge 100 includes a cartridge housing having a base plate 104 and a cover 110 secured to the base plate 104. The cover has a right-front corner portion as viewed in FIGS. 4 and 5, at which a top wall 112, a front wall and a side wall encounter with each other. A write enable plug 120 is provided on the top wall 112 adjacent the right-front corner and formed with a detection tab 122 projecting into a groove which is formed on an upper edge of the front wall. The detection tab 122 act as a detection section which is detectable by a sensing member on a tape drive (not shown). When the detection tab 122 is placed in its right-most position as seen in FIG. 5 by shifting the plug 120 in a direction as indicated by an arrow "A" of FIG. 5, writing on a magnetic recording tape is permitted. On the other hand, when the detection tab 122 is in its left-most position by shifting the plug 120 in a direction as indicated by an arrow "B" of FIG. 5, writing on the magnetic recording tape is prevented.
In order to prevent renewal or deletion of data stored on the magnetic recording tape due to inadvertent operation of the shiftable plug, a tape cartridge replaces the shiftable plug with a notch formed on a given plane surface of the cartridge housing, whereby the tape cartridge is employed as read-only one.
In a case where renewal or deletion of the data stored on such a read-only tape cartridge is carried out, the notch on the cartridge housing is covered with a masking material sheet such as an adhesive tape so that writing for the data renewal is allowed. Owing to the formation of the notch on the plane surface of the cartridge housing, the covering operation by using the masking material sheet is readily performed. In such a condition, the stored data tends to be undesirably renewed or deleted due to failing to remove the masking material sheet from the notch on the cartridge housing.
There is a demand to provide a tape cartridge having an improved housing structure which is capable of preventing inadvertent writing on a magnetic recording tape.